Posts Tagged ANZICE

The ANZICE program is certainly producing some intriguing results when viewed from a purely scientific perspective. But the serious implications of this research for the future of our environment and society give this work a pertinence beyond just the scientific community. Preliminary results are strongly suggesting that we have no time to lose in making significant changes towards a lower carbon economy.

Sean Weaver is an Honorary Research Associate in the School of Geography, Environment and Earth Sciences at Victoria University and now runs Carbon Partnership Ltd, a company that specialises in innovative climate change solutions through carbon financing, waste reduction and alternative energy sources. Sean is working towards synthesising the scientific results of ANZICE, interpreting the policy implications of those results and translating them into accessible and policy-relevant language.

At an international level, this process of translation is greatly facilitated by the Intergovernmental Panel on Climate Change. The IPCC seeks to achieve consensus on climate change issues, and to provide reliable information for the international policy community, based on rigorous scientific research. However, the IPCC’s effectiveness for informing policy has been systematically undermined by lobby groups, and their receptive audiences in government, bent on maintaining the status quo. The 5th Assessment Report of the IPCC is due in 2013 and the results of ANZICE will be directly contributing to this compendium through Working Group I (and to a lesser extent Working Group II).

In a world dominated by the quest for perpetual ‘growth’ one quarterly statement at a time, one of the biggest challenges for environmental planning is to convince government and business to invest in distant sustainable futures: to step back and perceive the value of the things that we currently take for granted (our inshore fisheries and our glacier-fed central South Island hydroelectric lakes are examples particularly relevant to ANZICE). Strategic management of our environment and resources is essential for safeguarding the quality of life of future generations. As the Greek proverb so eloquently puts it, “a society grows great when old men plant trees whose shade they know they shall never sit in”.

The climate is still a poorly understood system. But this knowledge gap needs to be viewed as a challenge for, not a failure of, modern science, and public research funding needs to be targeted accordingly. Applied climate science initiatives like ANZICE can help clear up common misconceptions surrounding the complexities of the climate system, show us where our efforts for change will be most effective, and give a quantitative sense of just how much we stand to lose through complacency.

New Zealand is a geographically lonely place. It is the only major landmass between the tropics and Antarctica at these longitudes, and shares the southern mid-latitudes with only Patagonia and Tasmania. As such, it is a fantastic natural laboratory for investigating oceanic and atmospheric change in the southern hemisphere.

Our country is perpetually being ground down by the elements in response to rapid uplift. Terrigenous sediment makes its way down river systems to be distributed far into the deep ocean, forming thick, continuous sedimentary sequences. While the sediment itself can appear outwardly unadorned, the real story is locked within the calcareous remains of plankton that have lived their short time in our seas and subsequently dropped to the seafloor to be entombed within the layers of mud. The geochemistry of their tiny shells can be used as proxy data for ocean temperature and salinity, and to assess changes in ocean currents over time.

Phytoplankton are autotrophs and thus live in surface waters of the ocean. When conditions are right — when the waters are sufficiently warm, well-lit and rich in nutrients — massive algal blooms may be initiated, often forming along major ocean fronts. These populations of microscopic plants may be so extensive as to be easily visible from space. Such blooms are thought to flourish during warm periods — evidence of an extreme case being the chalk deposits now exposed in the famous white cliffs of Dover, formed during the super hothouse world of the late Mesozoic. Such blooms appear to be increasing off New Zealand today: can this be attributed to global warming?

This is one of the questions that the Southern Ocean — New Zealand Responses research stream of ANZICE is currently attempting to answer. Whether these blooms are driven primarily by ocean temperature, or by the amount of incoming solar radiation, is unknown. Answering this question is important because phytoplankton are the base of the marine food chain and so any changes at this level will propagate through the whole system. They also provide their own feedback into the climate system by producing atmospheric acids that act as condensation nuclei for clouds. The calcium carbonate tests of plankton also comprise a significant carbon sink in the deep ocean, particularly so in the Southern Ocean during glacial periods, as outlined in a very recent paper.

Along with marine microfossils in these seafloor sediments are the robust pollen grains of land plants, transported to their marine resting place by the vigours of water and wind. By coring these sediments from oceanographic research vessels, ARC scientists are able to identify changes in vegetation cover on land in response to climate change. This wealth of information is made even more valuable by the logistical challenges of sampling it. This work would not be possible without collaboration with GNS Science, NIWA and research groups abroad.

A recently initiated study by the group is a classic case of uniformitarianism; the geological premise that the present is the key to the past. Beneath the central South Island glacial lakes are hundreds of metres of finely layered silts. It is not known what this layering represents and so it is prudent to first understand the modern day processes in these lakes before starting to make inferences about the past. Instruments have been deployed to measure what happens on a monthly basis in terms of water and sediment flux through the Lake Ohau system.

Gavin Dunbar returned to the Antarctic Research Centre in 2005 after working at the Australian National University (ANU), where he was interested in the climate history of the Western Pacific as shown in coral and speleothem geochemical records. Gavin now leads the Southern Ocean — New Zealand Responses group of ANZICE and supervises a number of post-graduate students who he has seen become experts in their own fields.

To ask the question, ’How will Antarctica respond to a warmer world?’ is similar to pondering, ’What was the weather like in the United States last century?’ In both cases there are multiple layers of complexity — from persistent regional disparities to variability on a range of timescales — yet this is a question being tackled by Earth scientists around the world, including those in the Antarctic Climate Drivers cluster of ANZICE at the Antarctic Research Centre.

Originally from Bavaria, Nancy Bertler came to the ARC in 1999 to undertake a PhD in ice core research. Now, little more than a decade later, she has 10 Antarctic field seasons under her belt and leads the Antarctic Climate Drivers research stream of ANZICE. She also represents New Zealand in the International Trans-Antarctic Scientific Expedition (ITASE) and her work unites Victoria University and GNS Science through the Joint Antarctic Research Institute.

In this episode of Journeys to the Ice, Dr. Bertler points out the double-importance of Antarctica in climate change research, namely, its role as an archive of past climate records, and as an agent of dramatic and global environmental change in response to current and future anthropogenic-induced global warming. Nancy’s research is aimed at making sense of a small part of the large range of variability in Antarctic climate. By analysing climate proxies preserved in high resolution ice cores from relatively small glaciers on the Victoria Land coast (see this previous posting/episode for further information), Nancy’s work has shown that episodic cooling in this part of Antarctica is caused by the shifting pathways of Southern Ocean air masses; a climate phenomenon now known to be driven by the El NiÃ±o Southern Oscillation.

Beneath the myriad of spatially- and temporally-localised intricacies in Antarctic climate however, are some undeniable and ubiquitous trends. A landmark study published last year by a research group led by Eric Steig of the University of Washington, found that the 50-year record of measurements from Antarctic weather stations (complemented by 30 years of satellite data) shows an Antarctic-wide warming trend, including a particularly marked warming in West Antarctica and the Ross Sea.

This finding, along with the historically unprecedented collapse of numerous small Antarctic ice shelves in recent decades and the discovery that the Southern Ocean is warming to depth, raises major concern about the stability of the Ross Ice Shelf, another focus of the Antarctic Climate Drivers group. The Ross Ice Shelf, the largest on Earth, separates the West Antarctic Ice Sheet, which is largely grounded below sea level, from the open ocean. The loss of this floating natural barrier would put West Antarctica’s grounded ice in grave danger of melting and/or detaching, either of which would raise global sea level by up to six metres. By collecting a 780 metre-long ice core from Roosevelt Island, near the present day seaward edge of the ice shelf, Nancy’s team hopes to reconstruct the retreat of the ice shelf during recent warm extremes and identify the threshold temperatures for complete collapse.

It is ironic that a science initiative called ANZICE should be concerned with investigating times in our geological past when there was relatively little of the cold, slippery stuff around.

The Antarctica — New Zealand Interglacial Climate Extremes program, currently underway at the Antarctic Research Centre, is aimed at better understanding the relationships between Antarctica, New Zealand and global climate. By reconstructing environmental responses to episodes of past warmth, regional climate models can be developed. Peak warm periods (interglacials) such as Marine Isotope Stage 5e (~125,000 years ago), when atmospheric and surface ocean temperatures were up to 3°C warmer than today, are important analogs for the climatic conditions predicted for the next century by the IPCC.

The general public and media do not necessarily appreciate the complexities of this science and so it needs to be translated into an easily digestible form. It is particularly important to be able to communicate the results to those who will ultimately make the decisions about how we manage our environment in the future. By understanding past climate, ANZICE will be well-placed to advise policy makers on what changes to expect in the New Zealand — Antarctic region in a warmer world of the future.

ANZICE comprises three research streams:

Antarctic Climate Drivers

Southern Ocean — New Zealand Responses

Climate Modeling

High-resolution ice cores from Antarctic coastal glacier sites are expected to document the Holocene Climatic Optimum by atmospheric gases, isotopes of water, major and trace elements, dust, and various compounds. Marine plankton, such as foraminifera, preserved in seafloor sediments provide valuable climate-related elemental and isotopic information in their sand-sized shells. The environmental response of terrestrial New Zealand can be gauged by studying lake sediments. These disparate environmental data, combined with the dynamics of temperate glaciers here in New Zealand, are used to generate empirical and computer-based climate models. These models are currently being fine-tuned, but are already proving to be extremely powerful scientific tools.

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